In a typical communications network, a device communicates via a Radio Access Network (RAN) to one or more Core Networks (CNs). The communications network may also be referred to as a wireless communications network, a wireless communications system, a communications network, a communications system, a network or a system, etc.
A subscriber may use the device to access services offered by an operator's network and services outside the operator's network to which the operator's radio access network and core network provide access (e.g., access to the Internet). The device may be any device, mobile or stationary, enabled to communicate over a radio channel in the communications network, for instance but not limited to user equipment, a mobile phone, a smart phone, sensors, meters, vehicles, household appliances, medical appliances, media players, cameras, Machine to Machine (M2M) device, a television, a radio, lighting arrangements, a tablet computer, laptop, a personal computer (PC), or any other type of device. The device may be portable, pocket storable, hand held, computer comprised, a vehicle mounted device that is enabled to communicate voice and/or data, via the radio access network, with another entity, such as another device or a server. The device may also be a wireless device.
The communications network covers a geographical area which is divided into cell areas. Each cell area is served by a base station. The base station may be referred to as a Radio Base Station (RBS), evolved Node B (eNB), eNodeB, NodeB, B node or Base Transceiver Station (BTS), etc., depending on the technology and terminology used. The base stations communicate over the air interface by operating at radio frequencies within range of the base stations.
IP multimedia core network subsystems (IMS) is an architectural framework for delivering IP multimedia service. A device may connect to IMS via fixed access (e.g., wired), mobile access or wireless access. The IMS comprises all core network elements for provision of multimedia services and is a collection of different functions, linked by interfaces. One or more functions may be combined in one network node, or a single function may be split into two or more network nodes. Each network node can also be present multiple times in a single network. IMS enables Public Land Mobile Network (PLMN) operators to offer their subscribers multimedia services based on and built upon Internet applications, services and protocols. The complete solution for the support of IP multimedia applications comprises devices, IP-Connectivity Access Networks (IP-CAN), and specific functional elements/functions of the IP multimedia core network subsystem.
The IMS comprises a Home Subscriber Server (HSS), or User Profile Server Function (UPSF). The UPSF is a user database that supports the IMS network entities that actually handle calls. A Call Session Control Function (CSCF) provides processing of SIP signaling packets in the IMS. There are several types of CSCF, such as e.g. Proxy-CSCF (P-CSCF), Serving-CSCF (S-CSCF) and Interrogating-CSCF (I-CSCF). The system also comprises application and media servers, a breakout gateway, and media resources.
Policy and Charging Control (PCC) is an important feature in a communications network. The PCC comprises a Policy and Charging Rules Function (PCRF) which provides policy control and flow based charging control decisions; and a Policy and Charging Enforcement Function (PCEF) implemented in a GateWay (GW) which enforces gating and Quality of Service (QoS) for individual IP flows according to PCC rules on the behalf of the PCRF; and provides usage measurement to support charging. Gx is the reference point between PCRF and PCEF and Rx is the reference point is between an Application Function (AF) and the PCRF.
A PCC rule comprises information necessary for enabling detection of a service data flow and providing parameters for policy control and/or charging control. A PCC rule may be dynamic or predefined. The dynamic PCC rule is provisioned by the PCRF via the Gx reference point. The predefined PCC is directly provisioned into the PCEF and only referenced by the PCEF.
Present methods for resource reservation with the 3rd Generation Partnership Project (3GPP) PCC framework supports that a service can get specific Guaranteed Bit Rate (GBR) resources specifically reserved. Describing the service in terms of packet filters identifies which data packets are part of the service. There is a GBR value (one for each direction) associated with those filters in order to express the demand for a GBR. Admission control procedures assure that enough resources are set aside for that data flow.
For a service layer, like IMS, there is an occasional need to run two or more mutually exclusive instances of the same kind of service and to quickly toggle between them in case of call waiting, call hold and call switching. Resources are exclusively reserved for each call. Examples of services are voice and video. When, for example, a resource reservation request for the second voice call arrives at the PCRF, resources for that call will be allocated even though only one of the calls are active while the other call is on hold or is waiting. Thus, an unnecessary large amount of radio resources are allocated. A service layer, as mentioned above, is a conceptual layer within a network service provider architecture which serves third-party value-added services and applications at a higher application layer. The service layer also provides an interface to core networks at a lower resource layer. The lower layers may be a control layer and/or a transport layer. The service layer of an IMS architecture provides multimedia services to the overall IMS network. In addition to IMS, the concept of service layer is used in other contexts such as Intelligent Networks (IN), Wireless Application Protocol (WAP) and Third Generation (3G).
The 3GPP PCC architecture accepts authorizations for media and their QoS demand over the Rx reference point. Each media has a separate authorization and obtains its own GBR resource reserved for that particular media.
For services that are mutually exclusive, the PCC framework offers no possibility to share the full or parts of the reserved resources between the mutually exclusive services, provided that other policy aspects like gating, identification of usage data for offline charging, etc., are still to be handled separately for each service. In particular, gating may be of importance to assist the application layer to ensure the services are mutually exclusive.
FIG. 1 illustrates embodiments of a method. A QCI-1 bearer with resources for a first call is reserved. Then, a second resource reservation is done from the P-CSCF when the next call is setup. As the same QCI and ARP will be used, a modification of existing bearer can be performed. However, for the new resources (which is a separate Rx session), the request from PCRF will use a different “Charging-Rule-Name AVP”. As a result, the PCEF will ADD the new resources requested on top of already allocated resources rather than update current resources. Thus, Call waiting, Call Hold, and Conferencing may today create double (and in some cases triple) resource reservation in the network. In all these cases, the user will only have one active call, the other session will be on hold. Still, dedicated resources will be allocated also for sessions where media is not sent/received. This leads to a waste of resources in the network, and requires over-dimensioning of the LTE cells. This may become a long term problem for populated areas, and in particular in areas with a large concentration of, e.g., business users, where an over-dimensioning will then be required.